Conventionally hologram recoding media including a recording layer on which information can be recorded as holograms are well-known, and the recording layer is typically formed of photopolymer or the like.
However, since the recording material such as photopolymer is likely to thermally deform, there is a problem that the recording layer is deformed (shrunk) when irradiated with a laser beam or exposed for fixation during recording or due to variations in temperature of storage places, resulting in variations in its reproduction properties such as diffraction efficiency.
As one of the means for solving such problems, a method for reducing shrinkage of a recording material has been suggested, e.g., as described in D. A. Waldman, “Journal of Imaging Science and Technology,” 1997, vol. 41, no. 5, p. 497-514.
However, such a method did not succeed in completely eliminating the deformation of a recording material. Thus, there was still a problem that the deformation of the recording layer lead to different shapes of a hologram during recording and during reproducing, resulting in variations in the reproduction properties such as diffraction efficiency.